Method and means for reproduction of sound



May 20, 94L G. P. REGAN ETAI. I'2,242,548

METHOD AND'MEANS FOR REPRODUCTION OF SOUND I v Filed sept. 2s, 193s s sheets-sheet 1 smi . o a v 650365 j? .E56/4N gif [22E/vz Fopoe May 20, 1941. e. P. REGAN ETAL.

METHOD @ND MEANS FOR REPRODUCTION OF SOUND v5 Sheets-Shale?. 2

Filed Sept. 28, 1938 me/Mms 650,26 H REQAN Fines/vz Af. fonce May 20, l9 41- G; P. REGAN E-r'AL 2,242,548

METHOD AND MEANS FOR REPRODUCTION OF SOUND Filed Sept. 28, 1.958 3 Sheets-Sheet 3 Patented May 20, 1941 T F i METHOD AND MEANS FOR REPRODUCTION F SOUND George P. Regan, North Hollywood, and Fcrenz H. Fodor, Los Angeles, Calif., assignors to Regan-Day, Inc., Los Angeles, Calif., a corporation of California Application September 28, 1938, Serial No. 232,138

14 Claims. (Cl. P19-100.3)

This invention pertains to means and methods of controllably reproducing sound from a plurality of longitudinally extending, substantially parallel recordings carried upon a suitable carrier strip such as continuous strip lm. When used for broadcasting purposes, the invention permits the continuous uninterrupted production of sound for a very protracted period of time from only a short length of nlm. Novel means are provided for regulating and controlling the direction of travel of the film in accordance with the particular record which is being reproduced, selection being thus made out of the number carried by the iilm.

The invention also relates to means and methods for holding, supporting and advancing continuous strip nlm or the like without the use of sprocket holes, thereby reducing the wear and strain imposed on ilm. The apparatus contemplates the use of a light source and a reproducing pick-up, and means are provided for selectively passing light from the source through the nlm and onto the pick-up.

More specifically stated, the apparatus of the invention includes a film-supporting drum consisting of a plurality of spaced circular disc elements mounted upon a hollow driven shaft, means being provided for applying suction to the shaft. Conduits connect spaces between the disc elements and the shaft, suction being thus caused to maintain the film in contact with the major portion of the periphery of the drum. The strip iilm is fed onto the drum from any suitable reel or magazine and is then taken oi the drum onto another reel. The apparatus also includes an optical system adapted to project and pass light through the iilm onto a reproducing pick-up. In the event lm thus carried is providedwith a plurality of transversely spaced but longitudinally extending sound records, means are provided for permitting light passing through only desired transverse portions of the lm to pass onto the reproducing pick-up. The apparatus al-so includes means for driving the drum and shaft and although such means may assume various forms, the electromagnetic means for rotating the drum shaft and for reversing the rotation thereof which are described and claimed in a co-pending application entitled Electromagnetic control device, iiled Sept. 28, 1938, under Ser. No. 232,- 137, issued Oct. 24, 1939, as Patent No. 2,176,897, is particularly Well adapted for use in conjunction with the apparatus of this invention.

It is an object of the present invention, therefore, to provide means for controllably reproducing sound from continuous strip films carrying a plurality of sound recordings.

Another object is to provide means for supporting and moving continuous strip lm in a ready and economical manner without the use of sprocket holes.

A further object is to provide means whereby sound may be controllably reproduced from a plurality of longitudinally extending, substantially parallel recordings carried upon strip lrn.

A still further object is to provide means and methods for regulating and controlling the direction of travel of film in accordance with the location of a record carried by the film and being reproduced.

These and other objects, uses and advantages o-f the invention will be more apparent to those skilled in the art from the following description of certain illustrative embodiments of the inven tion.

In order to facilitate explanation of the invention, reference will be had to the appended drawings, in which:

Fig. 1 is a general side elevation of one form of apparatus embodying the invention.

Fig. 2 is a view of the front of the device with the cover removed and part of the device in section.

Fig. 3 is a vertical section taken along the plane III--III of Fig. 2.

Fig. 4 is a diagrammatic representation of a strip of film bearing sound recordings thereon.

Fig. 5 is an enlarged View in vertical section of the film-supporting means embodied in Fig. 3.

Fig. 6 is a plan View of a masking element.

Fig. '7 is a-wiring diagram in which certain of the elements are diagrammatically represented.

Although the `invention may be embodied in devices capable of. many uses, the description given herein shall particularly refer to the use of the invention in an apparatus for the reproduction of sound either continuously or in a predetermined controlled manner. may include a base l on which there are movably positioned a gear housing 2, a clutch housing 3 and a reproducing housing 4, the-latter being provided with a removable door or panel 5. An axial vertical section through the reproducing housing l is shown in Fig. 3, a front view thereof being shown in Fig. 2.

By referring to Figs. 2 and 3 it will be seen that the base I is provided with a movably positionable partition member 6 in which there is journaled a driven member or driven shaft, generally indicated at l, such driven member car- 'I'he apparatus to a sleeve 22.

seen that perforations or ports 23 are formed rying a film-supporting drum 8.' The driven member 1 may be in axial alignment with driving shafts extending through the clutch housing 3 and the gear housing 2 and generally indicated at 9 (Fig. l), such driving shaft carrying the fly wheels and and being driven by means of drive shafts l2 and |3 connected to motors, not shown, but capable of driving the shafts 9, suitable clutch means being contained in the housing 3 whereby the driven member 1 may be coupled to the driving members and shafts so as to rotate the driven member 1 in desired directions.

The arrangement of the clutches, driving shafts, etc., contained within the housings 2 and 3 is shown in the co-pending application entitled Electromagnetic control device referred to hereinbefore. For the purposes of the instant case, it may be said that the clutch housing 3 contains electromagnetic coils, one driven in one f direction and the other in an opposite direction, such coils being capable of acting upon a plate element mounted upon one end of the driven shaft 1. By suitable electrical connections, which Will be described hereinafter, these driving coils are selectively energized so as to impart desired rotation to the driven member 1. Although particular reference has been made to electromagnetic means for controllably rotating the driven shaft 1, it will be understood that other methods and means for controllably rotating the driven member 1 may be employed. By referring to Figs. 2 and 3, it will be seen that the driven shaft 1 is hollow and is provided with a forwardly extending portion 1a of smaller diameter than the rear portion 1b. The portions 1a and 1b may be unitary or they may be separately made and then suitably connected together as by bracing. By reason of the difference in external diameters of different portions of the driven shaft 1, it is possible to maintain such driven shaft in rotatable position but restrain it from axial movement. For example, the fiange I I2 may cooperate with the bearings ||3 whereas the bronze bushing |44 carried by another partition, not shown, prevents movement of the driven shaft 1 in the opposite direction. The driven shaft 1 is preferably hollow, the outer end thereof being sealed as by means of a cap. Surrounding a portion of the hollow shaft 1 is a chamber |5 pinned to the partition 6 and containing sealing rings IE and |1. Ports |8 are formed in the cylindrical Walls of the driven shaft 1 communicating with the annular space formed by the housing I5. 'Ihe housing I5 is in turn connected as by means of the conduit I9 with a source of vacuum or suction, not shown. The interior of the driven hollow shaft 1 is thus supplied with suction and such suction is employed in holding strip lm in positive contact with the drum 8 mounted upon the driven meniber.

The drum 8 as shown in the illustrative embodiments of this invention, may comprise a plurality of disc-like elements or wheels, each consisting of a rim 2D and hollow spokes 2|. The rim and spokes of each disk-like element or Wheel may be made from hollow tubing and attached By referring to Fig. 5 it will be in the sleeve 22 and communicate with the hollow spokes 2 I The outer surfaces of the rim members 2B are also provided with peripherally spaced perforations or ports 24. Disc-like end plates 25 and 2b extend somewhat beyond the periphery of the rim members 20 and form radially extending iianges adapted to prevent transverse Weaving of the film 21 supported by the rim elements 20.

In actual construction the various disc-like or Wheel-like elements of the drum have their outer surfaces ground and polished soas to produce a true drum adapted to support the film 21 on a cylindrical surface. The various wheels or discs are spaced, however, as shown in Fig. 5 for a purpose and in a manner more readily understood by subsequent description.

The entire drum assembly is then mounted upon the driven hollow shaft 1 which is also provided with a plurality of wall openings, such as the openings 28 communicating the interior of the driven shaft 1 with the ports 23 and with the hollow disc-like drum elements including spokes 2| and rims 20. Since the interior of the hollow shaft 1 is under vacuum, suction is exerted through ports 28, 23, spokes 2| and perforations 24 upon the surface of the film 21.

When the apparatus of this invention is employed for the reproduction of sound recordings carried on film magazine, benefit is derived by employing a film such as the film 21 (Fig. 4) bearing a plurality of longitudinally extending, substantially parallel spaced sound recordings as, for example, the sound recordings 3|, 32, 33 and 34. When such film with its plurality of sound recordings is supported by the periphery of drum 8, it Will be found that the edge areas of the lml adjacent the longitudinal margins of each sound record carried by the film is supported by the drum. The film is caused to lie fiat upon the drum by reason of the suction exerted thereon' through the perforations or apertures 24. Transverse movement or weaving ofthe film is prevented by reason of the disc-like members 25 and 26 which cooperate with the longitudinal edges of the film strip 21. By supporting the filIn in such manner that areas adjacent the 1ongitudinal edges of each longitudinally extending sound record are in contact with and supported by the rims of the wheels or discs constituting the drum, it becomes possible to advance the film in any desired direction and to reproduce, seleotively, any one of the plurality of sound recordings carried by such film strip 21 without moving the film transversely.

Positioned below or at least to one side of the drum 8 is a light source, such as the incandescent lament source 4D removably positioned in a housing 4| and including a condensing lens system 42 and a further focusing and projecting lens system 43. The light source and its associated optical system carried by the housing 4| may be movably positionable on the partition 6 by means of the supporting anges 44 and 45, each thereof being provided with slots adapted toreceive machine screws 46 and 41 extending into tapped drillings within the partition 6. In Fig. 2 a duplicate light source and optical housing 4| is shown but only one will be described in detail.

Within the housing 4| is a slotted element 48 adapted to limit .the light of the condensing lens 42 into a slot or narrow beam which is then projected by the lens system 43 onto the film 21 carried by the drum. The optical elements from which the condensing lens 42 and the projecting lens 43 are made may be cylindrical so as to permit rthe projection of Ia plurality of separate narrow scanning beams on the surface of the fllm onlthe. drum. 8, each beam' fallingupon ai separate sound4 track y carried by the'filmi 21.

On .the opposite side of the. drumV 8 is a photoelectric pick-urp, generally indicated at 50, adaptedtoV receive light which may have been emitted by the light source 40 after i-t haspassed through the film 21 carried by the outer surface of thef drum 8. It will be notedthat in the drawings. another pick-up 50 is shown. Light emitted from the housing 4| will be picked up Iby .the photoelectric cell 5l] :but not by the pickupV 50' since the shaft 1 obstructs. the vision pick-up 50 to that point on the lm where the scanning beam emitted -by housing 4| is focused. Similarly, reproducing pick-up 58 will not pick up light -emitted by the h-ousing 4|' but only the scanning beam emitted by. housing` 4|. Reference will'be made subsequently. to the functions performed'by the. secondary lightbeam emitted =by housing 4|' and the secondary pick-up 50. Means are provided whereby the reproducing pickeupimay selectively receive light which is passed through any desired sound track only. Such means may comprise a masking element in the form of an arcuate member 52 provid-ed with an arcuate flange `53, said ange extending into amilled slot formed in a supporting bracket 54 carried by the partition 6. A rack 55 is formed in the outer rear portion of the masking member 52, said rack cooperating with .a pinion 56 mounted upon a shaft 51 journaled in .the partition 6 and provided at its other end with means for` adjustably and regulatably rotating the shaft 51.. It will `be evident that rotation of the shaft 51 will cause Ithe masking member 52 to move over the surface of the drum 8 and between said drumand the pick-up 58. The masking member. 52 isprovided with a :plurality of openings or:ports, such as theports 6|, 62, 63 `and 64, in staggered relation. It wil-l now be seen that since 'only one of the openings or ports 6 |-64 will be .inthe path of light between that point on the lower surface of the drum where the scanning lightsfarefocused and the pick-up V50, said pickup 50 will only be responsive to light observed through one of theportsBI-64. 'Ihe .ports 6|-64 -aretransversely spaceddistances equivalent to the spacing of thesound tracks 3 |-34 so that by adjustably positioning the masking memlber 52, the. pick-up 50 Ibecomes selectively responsive to only one ofthe number of sound records carried by the lm 21 over the drum 8.

A corresponding series of ports or openings 6| toB is also carried by the maskingmember 52, this secondary series of openings performing a similar function for the pick-up 58'..

Although various and sundry means may be usedin selectively and regulatably positioning the masking element so as to renderV the reproducing;pickup selectively responsive to a desired sound track carried by the lm on the drum 8, reference will be specifically made to an electrical method of so positioning the masking element. Such electrical method may involve the use .of -a solenoid 18 including aplu'rality -of coils 1|, 12, 13 and 14, the movable member ofthe solenoid including a rack ladapted tocooperate with and act upon a pinion.16 carried bythe shaft 51.

By now referring -to Fig. '1, the lcontrolled operation of the method will become evident. Fig. '1 shows the drum 8 mounted upon the driven shaft.:1,` which driven shaft is connected as at 1 toa plate 11. Theplate may be rotated in oppositedirections bymeans of driving poils, one

drivingicoil 'beingindicated .at RI and one at L, theJL -coil being :anuannular coil surrounding the coil R.' A braking coil B'is also shown, these .three coils'being capableof exerting their effect upon the plate member 11. When the coil R is energized, the driven member 1 will rotate in one direction; .when the coil B is energized, the drumf' will become stationary; when the coil L is energized, the drum 8 and its associated driven shaft 1 will rotate in `the opposite direction.

Current from one side of a line is connected to the drum 8; Resilient contact points 8|, 82, 83 and 84' are ordinarily positioned o-pposite certain of the discs or wheels constituting the drum Band ordinarilyare insulated from such drumsbyv the nlm itself. As shown in Fig. 4, however, the film 21 is provided with means capable of cooperating `with the spring-actuated iingers 8| to 84 so as to selectively permit'contact of such fingers with the drum 8. Such means lare shown in Fig. 4 .as perforations'or openings. 9|, 92, 93 and 94. The openings or perforations'Sl and 93 are .positioned at the ends of recordings 3| and 33 lwhereas the perfor-ations 92'and'94 are positioned operably with respect to the'ends of recordings 32 and 34. It is to be understood that recording 3| is reproducible from left to right whereas recording 32 is reproducible only from right to left.

When,` for example, spring contact 8| extends -through laperture 9| and makes contact with the drum 8, the selector relay |00, and particularly the relay IUI, is energized, current now flowing from one side of the line 80 through the drum and through the contact 8| into the relay |80 and through line 99 to the other side of the line. When the relay |0| is energized in the manner stated, currentis supplied Itothe coil 1| `of the solenoid 18, causing the member 15 to advance the masking element 52 fa desired predetermined distance. Simultaneously, however, a directional relay of the locking type indicated at ||0 is energized, this relay causing current to be supplied through the appropriate driving coil and thus driving the drum 8 in a direction correlated with the transverse position :of the sound record'which is now in position for reproduction.

The relay. points -|8| arethe only sets shown in the drawings as supplied-with current from the main line 80 by conductors |89 but it is to be understood that the other upper sections` of the individual relay points such as |82, are similarlyv supplied with current.

It' will thus be seen that the apparatus of this invention is well adapted to the continuous reproductionof sound from a plurality of records carried by a strip of film, the direction of movement of the. film being automatically changed concurrentlywith changes in the transverse location of a scanning light received by the reproducing pick-up. Furthermore, the transverse location of light passed through the iilm onto the pick-up is automatically varied in accordance with signals carried by the nlm, such signalsin the illustrative example given comprising the ports or apertures 6| to 6d of the masking member 52.

changed automatically by the masking member 52 in accordance with the signals` carried by the film but in addition the direction of movement of the film isvariedand-automatically changed inaccordancefwith such signals;` In other words,

Not only is the transverse location oflight passed through the film onto the pick-up' it may be stated that the direction of movement of the film, changes in the transverse location of light passed through the film onto the pick-up and the signals or actuating means carried by the iilm are all interrelated and mutually affect each other.

In the description given hereinabove particular reference has been made to the reproducing pick-up 5l). In the event the apparatus of this invention is to be employed in the selective reproduction of sound from the various records carried by the lm so that individual phrases or portions of each record are to be reproduced, or when it is desired to automatically terminate the reproduction of sound at the end of a phrase and then selectively initiate subsequent reproduction at the beginning of a succeeding phrase in the record, then the relay pick-up 50 and its associated secondary light source 4l is employed.

Complete data regarding the use of a relay pick-up 5D' in this manner is described in detail in Patent No. 2,094,847 issued October 12, 1937, to Regan and Franklin. The relay control shown in this patent may be used to advantage in controlling the electromagnetic coils for driving the film-advancing drum in desired directions and in stopping the drum at the` required point.

Furthermore, it is to be understood that the film-advancing means may be used whenever it is desired to manually control the operation so that the entire method and apparatus may be carried'out manually without reliance upon the automatic control features referred to.

- Although the signal means carried by the film and specifically referred to hereinabove consisted of perforations or openings in the film, it will be understood that such signal means may assume different forms and may comprise, if desired, metallic inserts, notches, or the like. Moreover, the movement of the masking member may be accomplished pneumatically as', for example, by the use of vacuum, valves, cocks, stops, etc. being controlled either manually or by means of signalling or actuating devices carried by or formed in the film.

We claim:

1. An apparatus for substantially continuous reproduction of a plurality of transversely spaced longitudinally extending sound records carried i by strip lm, comprising: a drum for supporting and moving lm, means for rotating the drum in either direction and stopping the saine, a reproducing pick-up associated with said drum, stationary light sources adapted to pass light through various transverse portions of the lm While on said drum, movable light masking means for passing light through desired transverse portions of the film into operative relation with said pick-up, and means associated With the film carried upon said drum for actuating the light masking means to pass light through desired transverse portions only of the film.

2. An apparatus for substantially continuous reproduction of a plurality of transversely spaced longitudinally extending sound records carried by strip lm, comprising: a drum for supporting and moving film, means for rotating the drum in either direction and stopping the same, a reproducing pick-up associated with said drum, stationary light sources adapted to pass light through various transverse portions of the lm while on said drum, movable adjustable means for passing light through desired transverse portions of the lm into operative relation with said pick-up, an electrical circuit including' contacts cooperating with the film for regulating the direction of rotation of said drum in accordance with the location of the portion of lm through which light is being passed onto the pick-up.

3. An apparatus for substantially continuous reproduction of sound from a plurality of transversely spaced longitudinally extending sound records carried by strip film, comprising: a lmsupporting drum comprising a plurality of spaced circular disc elements mounted upon a driven hollow shaft, conduits communicating spaces between disc elements with the interior of the shaft, means for applying suction to the shaft during its rotation, means for rotating said hollow shaft, a light source, an optical system adapted to project light between said spaced disc elements and through film carried thereby, a reproducing pick-up in operative relation to the lm on said disc elements and said light source, and means in operative relation to said pick-up in the path of light from said source for selectively passing light through desired spaces between the disc into said reproducing pick-up.

4. An apparatus for substantially continuous reproduction of sound from a plurality of transversely spaced longitudinally extending sound records carried by strip film, comprising: a lmsupporting drum comprising a plurality of spaced circular disc elements mounted upon a driven hollow shaft, conduits communicating spaces between disc elements with the interior of the shaft, means for applying suction to the shaft during its rotation, means for rotating said hollow shaft, a light source, an optical system adapted to project light between said spaced disc elements and through lm carried thereby, a reproducing pick-up in operative relation to the lm on said disc elements and said light source, and means in operative relation to said pick-up in the path of light from said source for selectively passing light through desired spaces between the disc into said reproducing pick-up, said last-named means being actuated automatically by the lm.

5. A nlm advancing and supporting means comprising a plurality of hollow spaced rims with hollow spokes mounted upon a hollow shaft, said spaced rims forming a drum adapted to support a film; means for supplying suction to said shaft, conduit means connecting said shaft and spokes, and perforations in the outer film-supporting surfaces of said rims.

6. An apparatus for advancing and supporting strip film comprising: a plurality of hollow wheel elements mounted upon a hollow shaft, outer surfaces of said wheel elements lying in a cylindrical plane adapted to support film, said wheel elements being axially spaced whereby areas adjacent the longitudinal areas of sound records carried by said lm are supported by the outer surfaces of said wheel elements, means for applying suction to the interior of said wheel elements, suction ports formed in the outer surfaces of such wheel elements, and means for controllably rotating said shaft.

7. In an apparatus of the character described,

the combination of: a drum-like nlm-supporting means, a plurality of means for driving said filmsupporting means, means for selectively coupling said driving means with said film-supporting means; means for passing light through lm on said supporting means, a pick-up adapted to receive light passed through said film, means for lcontrolling light yreceived by the pick-up, and

means associated with the film carried upon said nlm-supporting means for adjustably positioning said means for controlling light received by the pick-up.

8. An apparatus adapted for substantially continuous reproduction of a plurality of transversely spaced longitudinally extending sound records carried by strip lm, comprising: a drum for supporting a moving strip film, said drum comprising a plurality of hollow spaced wheels, means for rotating the drum in either direction and stopping the same, a reproducing pick-up on one side of said drum, and a light source adapted to project a scanning light on various transverse portions of the film while on said drum, said light source being positioned on the other side of said drum and directed toward said reproducing pick-up.

9. An apparatus adapted for substantially continuous reproduction of a plurality of transversely spaced longitudinally extending sound records carried by strip film, comprising: a drum for supporting a moving strip nlm, said drum cornprising a plurality of hollow spaced wheels, means for rotating the drum in either direction and stopping the same, a reproducing pick-up on one side of said drum, a light source adapted to project a scanning light on various transverse portions of the iilm while on said drum, said light source being positioned on the other side of said drum and directed toward said reproducing pick-up, and means positioned in the path of light from said source to the said pick-up for regulatably controlling the transverse location of light passed through the lm onto the pick- 10. An apparatus adapted for substantially continuous reproduction of a plurality of transversely spaced longitudinally extending sound records carried by strip film, comprising: a drum for supporting and moving strip lm, said drum comprising a plurality of hollow spaced Wheels, means for rotating the drum in either direction and stopping the same, a reproducing pick-up on one side of said drum, a light source adapted to project a scanning light on various transverse portions of the film while on said drum, said light source being positioned on the other side of said drum and directed toward said reproducing pick-up; means positioned in the path of light from said source onto said pick-up for regulatably controlling the transverse location of light passed through the iilm onto the pick-up; and an electrical circuit including contacts cooperating with the nlm and adapted to energize the light controlling means to pass light through the desired transverse portions of the lm only.

1l. In an apparatus of the character described, a nlm supporting and advancing drum comprising a plurality of spaced wheels mounted upon a hollow shaft, the cylindrical edge areas of said wheels being adapted to lie in a common cylindrical surface adapted to support lm, a bearing for said shaft, means for restraining said shaft from movement in an axial direction, ports communicating with said hollow shaft, means for supplying vacuum to said ports, and a plurality of crcumierentially spaced suction ports in the cylindrical edge areas of said wheels.

12. In an apparatus of the character described, a nlm supporting and advancing drum comprisinCr a plurality of spaced wheels mounted upon a hollow shaft, the cylindrical edge areas of Said wheels being adapted to lie in a common cylindrical surface adapted to support iilm, a bearing 'for said shaft, means for restraining said shaft from movement in an axial direction, ports communicating with said hollow shaft, means for supplying vacuum to said ports, a plurality of circumferentially spaced suction ports in the cylindrical edge areas of said wheels, a reproducing pick-up on one side ci said drum, and a light source and optical system on the other side of said drum, said light source and optical system being adapted to project scanning beams upon lilm carried by said drum and towards said reproducing pick-up.

13. In an apparatus oi the character described, a nlm supporting andradvancing drum comprising a plurality of spaced wheels mounted upon a hollow shaft, the cylindrical edge areas of said wheels being adapted to lie in a common cylindrical surface adapted to support nlm, a bearing for said shaft, means for restraining said shaft from movement in an axial direction, ports communicating with said hollow shaft, means for supplying vacuum to said ports, a Vplurality of circumierentially spaced suction ports in the cylindrical edge areas of said wheels, a reproducing pick-up on one side of said drum, a light source and optical system on the other side of said drum, said light source and optical system being adapted to project scanning beams upon film carried by said drum and towards said reproducing pick-up, and a movable light-controlling and masking element between said pickup and light source for passing light through desired portions only of the film on said drum.

14. In a method of supporting and moving strip lm carrying a longitudinally extending sound record, the step of applying suction at a plurality oi points at areas adjacent both of the longitudinal edges of sound record carried by the iilm, and moving said points at which suction is applied whereby the iilm is moved bodily while the `sound track is maintained substantially flat.

GEORGE P. REGAN. FERENZ H. FODOR. 

